Fix another hyphen-used-as-minus-sign issue in nccopy.1 man page.
Fix another hyphen-used-as-minus-sign issue in nccopy.1 man page.

Most of these issues were fixed in #101, but the patch included in the Debian
package was updated afterwards to include this remaining issue.

Unidata/netcdf-c,Unidata/netcdf-c,Unidata/netcdf-c,Unidata/netcdf-c